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Diodes Incorporated MMSTA42-7-F
- Part No.:
- MMSTA42-7-F
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- SC-70, SOT-323
- Datasheet:
-
MMSTA42-7-F.pdf
- Description:
- TRANS NPN 300V 0.2A SOT-323
- Quantity:
- Payment:
- Shipping:
Inventory:263,608
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Product details
Overview
MMSTA42-7-F from Diodes Incorporated is an NPN small-signal surface-mount transistor in SOT-323 package, rated for 300 V VCEO, 200 mA IC, and 200 mW PD, optimized for low-power switching and amplification in space-constrained DC-DC feedback and signal routing circuits.
For engineers reviewing the MMSTA42-7-F datasheet, MMSTA42-7-F pinout, MMSTA42-7-F application, or MMSTA42-7-F equivalent, key selection criteria include high-voltage breakdown (300 V), low thermal resistance (625 °C/W), RoHS-compliant green molding compound, and verified SOT-323 terminal layout per MIL-STD-202 solderability standards.
Technical Context
This discrete NPN bipolar junction transistor uses epitaxial planar die construction to achieve stable high-voltage operation up to 300 V across collector-base and collector-emitter terminals, with guaranteed hFE of 25–40 at IC = 1–30 mA and VCE = 10 V.
It delivers fT = 50 MHz at VCE = 20 V and IC = 10 mA, and maintains VCE(SAT) ≤ 0.5 V at IC = 20 mA / IB = 2 mA, supporting fast-switching low-current control paths in isolated gate drivers and voltage monitor stages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 300 V - Enables use in 240 VAC-derived auxiliary rails and flyback snubber circuits without derating. |
| IC | 200 mA - Supports load switching for LED biasing, optocoupler drivers, and sensor interface stages. |
| PD | 200 mW - Requires minimal PCB copper area for thermal management on FR-4 boards per AP02001 layout. |
| hFE | 25–40 - Provides predictable current gain across -55°C to +150°C for analog sensing front-ends. |
| fT | 50 MHz - Sufficient for PWM frequency detection and low-speed digital signal conditioning. |
| RθJA | 625 °C/W - Matches thermal performance of comparable SOT-323 transistors under standard JEDEC test conditions. |
Pinout & Package
Package: SOT-323 - ultra-small surface-mount plastic case (2.00–2.20 mm × 1.15–1.35 mm × 0.25–0.40 mm height), UL 94V-0 rated, moisture sensitivity level 1, lead-free matte tin plating over Alloy 42 leadframe.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink reference node | Connected to ground or low-side return path; supports ≤200 mA continuous conduction. |
| Base (B) | Control input node | Drives with ≤2 mA to achieve full saturation; requires series resistor for current limiting in TTL/CMOS interfaces. |
| Collector (C) | High-voltage output node | Handles up to 300 V reverse-biased potential; used for open-collector outputs and active clamping. |
Key Features
| Feature | Design Value |
|---|---|
| Epitaxial planar die | Ensures consistent V(BR)CEO distribution and low leakage (<100 nA ICBO) across production lots. |
| SOT-323 footprint | Reduces board area by >40% vs. SOT-23 while maintaining compatibility with standard pick-and-place equipment. |
| Green molding compound | Halogen-free formulation compliant with IPC-4101D/102, eliminating Sb2O3 flame retardants in units dated 0627 and later. |
| Lead-free plating | Matte tin finish annealed over Alloy 42, certified to JEDEC J-STD-020C Level 1 reflow profile. |
Applications
| DC-DC Feedback Sensing | Optocoupler Driver Stage |
|---|---|
Use Scenario: Monitoring output voltage in isolated flyback converters via resistive divider and error amplifier. IC Role / Device Role / Timing Role: NPN switch translating error amplifier output into optocoupler LED drive current. Use Value: 300 V VCEO withstands reflected primary-side transients; 0.5 V VCE(SAT) minimizes power loss in feedback loop. | Use Scenario: Driving PC817 or similar optocouplers in industrial PLC I/O isolation modules. IC Role / Device Role / Timing Role: Low-power current-controlled switch interfacing microcontroller GPIO to optocoupler input. Use Value: Verified 200 mA IC rating ensures reliable LED forward current delivery; SOT-323 enables dense channel packing. |
| High-Voltage Signal Routing | Temperature-Stable Bias Generator |
Use Scenario: Selecting between multiple sensor inputs in HVAC control panels operating from 24 VAC mains-derived rails. IC Role / Device Role / Timing Role: High-voltage NPN switch enabling/disabling analog signal paths before ADC input. Use Value: 300 V VCBO prevents breakdown during AC line surges; hFE stability over -55°C to +150°C ensures consistent gain across environments. | Use Scenario: Generating precision reference currents for RTD or thermistor measurement circuits in automotive cabin sensors. IC Role / Device Role / Timing Role: Constant-current source configured with emitter degeneration resistor and base bias network. Use Value: Tight hFE tolerance (25–40) and low VBE(SAT) (≤0.9 V) reduce temperature-induced current drift in bias networks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN small-signal switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBT4401-7-F | VCEO = 40 V, IC = 600 mA, fT = 250 MHz - lower voltage, higher speed and current. | Not suitable for >60 V circuits; preferred in high-frequency logic-level switching where voltage stress is low. | Select when circuit operates below 40 V and requires faster turn-on/turn-off than MMSTA42-7-F provides. |
| BC847BW,115 | VCEO = 45 V, hFE = 110–220, RθJA = 350 °C/W - higher gain, better thermal performance, lower voltage rating. | Used in low-voltage analog amplification; unsuitable for 240 VAC-derived supply monitoring. | Choose for linear amplification in battery-powered instrumentation where gain consistency outweighs high-voltage capability. |
Compared with MMSTA42-7-F, MMST4401-7-F trades 300 V robustness for higher speed and current, while BC847BW offers superior hFE uniformity but cannot replace it in high-breakdown-voltage applications like auxiliary power monitoring.
Availability
MMSTA42-7-F is available at Aetrix Electronics and suitable for DC-DC feedback sensing, optocoupler driver stages, high-voltage signal routing, and temperature-stable bias generation requiring stable component supply across extended temperature ranges and long-lifecycle industrial programs.
Supply support for MMSTA42-7-F includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for power management, signal integrity, and protection applications.
The MMSTA42 belongs to Diodes' high-voltage small-signal transistor product line, engineered specifically for space-constrained, high-isolation applications such as auxiliary power monitoring, feedback loops, and industrial signal conditioning.
FAQ
What is the maximum allowable collector-emitter voltage for MMSTA42-7-F?
The absolute maximum VCEO is 300 V at TA = 25°C, verified per JEDEC JESD78 testing. Derating is required above 25°C ambient per Fig. 1 in DS30175 Rev. 10–2; at 100°C, maximum usable VCEO drops to approximately 220 V based on thermal limits and RθJA = 625 °C/W.
Is MMSTA42-7-F compatible with lead-free reflow processes?
Yes - MMSTA42-7-F uses matte tin plating over Alloy 42 leadframe and conforms to JEDEC J-STD-020C Level 1 moisture sensitivity. It supports peak reflow temperatures up to 260°C and is qualified for standard Pb-free SAC305 profiles without delamination or solder joint failure.
How does the SOT-323 package affect thermal performance compared to SOT-23?
Due to its smaller pad area and thinner mold compound, the SOT-323 package exhibits higher RθJA (625 °C/W) versus typical SOT-23 devices (~350–450 °C/W). This requires adherence to Diodes' AP02001 recommended PCB layout - including 1-inch × 0.85-inch copper pour - to maintain safe junction temperature under 200 mW dissipation.
Can MMSTA42-7-F be used as a direct replacement for MMSTA92 in complementary circuits?
No - MMSTA92 is the complementary PNP device; MMSTA42-7-F is NPN only. While both share SOT-323 packaging and similar voltage ratings, their polarity, biasing requirements, and current flow direction differ fundamentally. Circuit redesign is required to substitute one for the other in push-pull or differential pair configurations.
MMSTA42-7-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 200 mA
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 2mA, 20mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 40 @ 30mA, 10V
- Power - Max:
- 200 mW
- Frequency - Transition:
- 50MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
MMSTA42-7-F FAQ
1.How can I place an order for MMSTA42-7-F through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSTA42-7-F on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MMSTA42-7-F reliable?
The price and inventory of MMSTA42-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSTA42-7-F is usually 5 days.
3.What payment methods are accepted for MMSTA42-7-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSTA42-7-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSTA42-7-F?
MMSTA42-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSTA42-7-F order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MMSTA42-7-F?
For technical support, including MMSTA42-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSTA42-7-F requirements.
6.How does Aetrix verify that MMSTA42-7-F is sourced from the original manufacturer or authorized distributors?
All MMSTA42-7-F products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MMSTA42-7-F meets industry standards.
7.What is the process for return or replacement of MMSTA42-7-F?
All MMSTA42-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMSTA42-7-F, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MMSTA42-7-F part is unused and in its original packaging.
Return procedure for MMSTA42-7-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMSTA42-7-F Tags
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MMBT3906LT1G
onsemi
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MMBT3904-7-F
Diodes Incorporated
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MMBT3904LT1G
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MMBT3906-7-F
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MMBT3904-TP
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MMBT2222A-7-F
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BC846BLT1G
onsemi
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BC847B,215
Nexperia USA Inc.
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SMMBT3904LT1G
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MMBTA06LT1G
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MMBT2222ALT1G
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